1. Field of the Invention
The present invention relates to self-venting valves, and more particularly to a self-venting valve for draining water from fuel filter assemblies.
2. Description of the Prior Art
Self-venting liquid drain valves have been known in the art for many years. Specifically, various assemblies have been made to provide fluid drainage from a vessel while providing a separate inlet for gas, such as air, to replace the fluid being drained. For example, in fuel/water separators used in diesel engines, water must be periodically drained using a valve assembly adapted to feed air into a separator while the water is being drained. The prior art devices have accomplished this by providing separate air and liquid passages formed through a portion of the valve assembly member.
A problem that occurs with fluid filter assemblies, particularly useful for diesel engines and gasoline marine engines, is facilitating the removal of contaminants from the filter assembly. These contaminants include water and particulate matter that tend to settle at the bottom of housings used to retain filter elements. In order to remove the water and particulate matter suspended in the water, drain valves are frequently positioned at the bottom of housings used to retain filter elements. If a simple drain cock is utilized for the valve, the drainage may not be complete or may not occur at all because a partial vacuum is created in the filter housing upon initiating drainage. The partial vacuum prevents water from flowing through the open valve.
In order to facilitate drainage by breaking the partial vacuum, drainage valves in fuel filters are vented. It is necessary to close the vent hole when the valves are closed so that fluid within the fluid filter does not flow out through the vent hole. In prior art arrangements there is the possibility of vent holes becoming blocked by particulate debris suspended in the fuel or water at the bottom of the housing. This is because the end of the vent tube, which opens within the housing, is left continuously open so that over time particles can accumulate in the vent tube.
Furthermore, currently used drain valves are made of multiple parts that makes them expensive in manufacturing and laborious and difficult to assemble.